Many Americans fall short on calcium, which is essential for strong bones and overall health. Supplements can help make up for shortfalls, but we’ve advised getting as much calcium as you can from your diet because calcium-rich foods contain other bone-friendly nutrients. This is also good advice because of lingering concerns about the safety of high doses of calcium supplements, even though recent research on them has been reassuring.
You may have wondered where all those calcium-fortified foods—from fruit juices and soy milk to breakfast cereals, bottled waters, and energy bars—fit in this discussion. Is drinking fortified orange juice the same as taking a calcium pill with a cup of regular juice? Here’s what you need to know:
- Calcium-fortified foods are a good option for people who don’t like or can’t tolerate dairy products. But they are more like supplements than natural sources of calcium.
- The calcium in fortified foods varies greatly in its bioavailability (how well the body is able to absorb and use it), depending on the form of calcium used and how it’s affected by other substances in the food. Most studies have found that the calcium in fortified orange juice is as well utilized as that in milk. But few other calcium-fortified foods have been tested in terms of their bioavailability, and none have been tested for their effects on bone health.
- Calcium added to beverages—such as soy drinks—can settle to the bottom of the containers. Even if you shake the bottle, you may get inconsistent amounts of calcium.
- Because calcium is being added to more and more foods, it’s possible to inadvertently get far more than the recommended 1,000 to 1,200 milligrams a day—especially if you also take a supplement. High doses of supplemental calcium increase the risk of certain kinds of kidney stones. In contrast, foods naturally rich in calcium (notably dairy products) seem to protect against kidney stones. But fortified foods have not been studied in this regard. High doses of calcium can also interfere with certain drugs, such as thyroid hormones, corticosteroids, and tetracycline.
Bottom line: Natural sources of calcium are preferable, but fortified foods and supplements, consumed judiciously, have their place too.